xref: /linux/drivers/bluetooth/hci_vhci.c (revision bba2c3615bd6cfee7456d1130f2e6b01b3f4e9ba) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  *  Bluetooth virtual HCI driver
5  *
6  *  Copyright (C) 2000-2001  Qualcomm Incorporated
7  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
8  *  Copyright (C) 2004-2006  Marcel Holtmann <marcel@holtmann.org>
9  */
10 
11 #include <linux/module.h>
12 #include <linux/unaligned.h>
13 
14 #include <linux/atomic.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/types.h>
19 #include <linux/errno.h>
20 #include <linux/sched.h>
21 #include <linux/poll.h>
22 
23 #include <linux/skbuff.h>
24 #include <linux/miscdevice.h>
25 #include <linux/debugfs.h>
26 
27 #include <net/bluetooth/bluetooth.h>
28 #include <net/bluetooth/hci_core.h>
29 
30 #define VERSION "1.5"
31 
32 static bool amp;
33 
34 struct vhci_data {
35 	struct hci_dev *hdev;
36 
37 	wait_queue_head_t read_wait;
38 	struct sk_buff_head readq;
39 
40 	struct mutex open_mutex;
41 	struct delayed_work open_timeout;
42 	struct work_struct suspend_work;
43 
44 	bool suspended;
45 	bool wakeup;
46 	__u16 msft_opcode;
47 	bool aosp_capable;
48 	atomic_t initialized;
49 };
50 
51 static int vhci_open_dev(struct hci_dev *hdev)
52 {
53 	return 0;
54 }
55 
56 static int vhci_close_dev(struct hci_dev *hdev)
57 {
58 	struct vhci_data *data = hci_get_drvdata(hdev);
59 
60 	skb_queue_purge(&data->readq);
61 
62 	return 0;
63 }
64 
65 static int vhci_flush(struct hci_dev *hdev)
66 {
67 	struct vhci_data *data = hci_get_drvdata(hdev);
68 
69 	skb_queue_purge(&data->readq);
70 
71 	return 0;
72 }
73 
74 static int vhci_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
75 {
76 	struct vhci_data *data = hci_get_drvdata(hdev);
77 
78 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
79 
80 	skb_queue_tail(&data->readq, skb);
81 
82 	if (atomic_read(&data->initialized))
83 		wake_up_interruptible(&data->read_wait);
84 	return 0;
85 }
86 
87 static int vhci_get_data_path_id(struct hci_dev *hdev, u8 *data_path_id)
88 {
89 	*data_path_id = 0;
90 	return 0;
91 }
92 
93 static int vhci_get_codec_config_data(struct hci_dev *hdev, __u8 type,
94 				      struct bt_codec *codec, __u8 *vnd_len,
95 				      __u8 **vnd_data)
96 {
97 	if (type != ESCO_LINK)
98 		return -EINVAL;
99 
100 	*vnd_len = 0;
101 	*vnd_data = NULL;
102 	return 0;
103 }
104 
105 static bool vhci_wakeup(struct hci_dev *hdev)
106 {
107 	struct vhci_data *data = hci_get_drvdata(hdev);
108 
109 	return data->wakeup;
110 }
111 
112 static ssize_t force_suspend_read(struct file *file, char __user *user_buf,
113 				  size_t count, loff_t *ppos)
114 {
115 	struct vhci_data *data = file->private_data;
116 	char buf[3];
117 
118 	buf[0] = data->suspended ? 'Y' : 'N';
119 	buf[1] = '\n';
120 	buf[2] = '\0';
121 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
122 }
123 
124 static void vhci_suspend_work(struct work_struct *work)
125 {
126 	struct vhci_data *data = container_of(work, struct vhci_data,
127 					      suspend_work);
128 
129 	if (data->suspended)
130 		hci_suspend_dev(data->hdev);
131 	else
132 		hci_resume_dev(data->hdev);
133 }
134 
135 static ssize_t force_suspend_write(struct file *file,
136 				   const char __user *user_buf,
137 				   size_t count, loff_t *ppos)
138 {
139 	struct vhci_data *data = file->private_data;
140 	bool enable;
141 	int err;
142 
143 	err = kstrtobool_from_user(user_buf, count, &enable);
144 	if (err)
145 		return err;
146 
147 	if (data->suspended == enable)
148 		return -EALREADY;
149 
150 	data->suspended = enable;
151 
152 	schedule_work(&data->suspend_work);
153 
154 	return count;
155 }
156 
157 static const struct file_operations force_suspend_fops = {
158 	.open		= simple_open,
159 	.read		= force_suspend_read,
160 	.write		= force_suspend_write,
161 	.llseek		= default_llseek,
162 };
163 
164 static ssize_t force_wakeup_read(struct file *file, char __user *user_buf,
165 				 size_t count, loff_t *ppos)
166 {
167 	struct vhci_data *data = file->private_data;
168 	char buf[3];
169 
170 	buf[0] = data->wakeup ? 'Y' : 'N';
171 	buf[1] = '\n';
172 	buf[2] = '\0';
173 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
174 }
175 
176 static ssize_t force_wakeup_write(struct file *file,
177 				  const char __user *user_buf, size_t count,
178 				  loff_t *ppos)
179 {
180 	struct vhci_data *data = file->private_data;
181 	bool enable;
182 	int err;
183 
184 	err = kstrtobool_from_user(user_buf, count, &enable);
185 	if (err)
186 		return err;
187 
188 	if (data->wakeup == enable)
189 		return -EALREADY;
190 
191 	data->wakeup = enable;
192 
193 	return count;
194 }
195 
196 static const struct file_operations force_wakeup_fops = {
197 	.open		= simple_open,
198 	.read		= force_wakeup_read,
199 	.write		= force_wakeup_write,
200 	.llseek		= default_llseek,
201 };
202 
203 static int msft_opcode_set(void *data, u64 val)
204 {
205 	struct vhci_data *vhci = data;
206 
207 	if (val > 0xffff || hci_opcode_ogf(val) != 0x3f)
208 		return -EINVAL;
209 
210 	if (vhci->msft_opcode)
211 		return -EALREADY;
212 
213 	vhci->msft_opcode = val;
214 
215 	return 0;
216 }
217 
218 static int msft_opcode_get(void *data, u64 *val)
219 {
220 	struct vhci_data *vhci = data;
221 
222 	*val = vhci->msft_opcode;
223 
224 	return 0;
225 }
226 
227 DEFINE_DEBUGFS_ATTRIBUTE(msft_opcode_fops, msft_opcode_get, msft_opcode_set,
228 			 "%llu\n");
229 
230 static ssize_t aosp_capable_read(struct file *file, char __user *user_buf,
231 				 size_t count, loff_t *ppos)
232 {
233 	struct vhci_data *vhci = file->private_data;
234 	char buf[3];
235 
236 	buf[0] = vhci->aosp_capable ? 'Y' : 'N';
237 	buf[1] = '\n';
238 	buf[2] = '\0';
239 	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
240 }
241 
242 static ssize_t aosp_capable_write(struct file *file,
243 				  const char __user *user_buf, size_t count,
244 				  loff_t *ppos)
245 {
246 	struct vhci_data *vhci = file->private_data;
247 	bool enable;
248 	int err;
249 
250 	err = kstrtobool_from_user(user_buf, count, &enable);
251 	if (err)
252 		return err;
253 
254 	if (!enable)
255 		return -EINVAL;
256 
257 	if (vhci->aosp_capable)
258 		return -EALREADY;
259 
260 	vhci->aosp_capable = enable;
261 
262 	return count;
263 }
264 
265 static const struct file_operations aosp_capable_fops = {
266 	.open		= simple_open,
267 	.read		= aosp_capable_read,
268 	.write		= aosp_capable_write,
269 	.llseek		= default_llseek,
270 };
271 
272 static int vhci_setup(struct hci_dev *hdev)
273 {
274 	struct vhci_data *vhci = hci_get_drvdata(hdev);
275 
276 	if (vhci->msft_opcode)
277 		hci_set_msft_opcode(hdev, vhci->msft_opcode);
278 
279 	if (vhci->aosp_capable)
280 		hci_set_aosp_capable(hdev);
281 
282 	return 0;
283 }
284 
285 static void vhci_coredump(struct hci_dev *hdev)
286 {
287 	/* No need to do anything */
288 }
289 
290 static void vhci_coredump_hdr(struct hci_dev *hdev, struct sk_buff *skb)
291 {
292 	const char *buf;
293 
294 	buf = "Controller Name: vhci_ctrl\n";
295 	skb_put_data(skb, buf, strlen(buf));
296 
297 	buf = "Firmware Version: vhci_fw\n";
298 	skb_put_data(skb, buf, strlen(buf));
299 
300 	buf = "Driver: vhci_drv\n";
301 	skb_put_data(skb, buf, strlen(buf));
302 
303 	buf = "Vendor: vhci\n";
304 	skb_put_data(skb, buf, strlen(buf));
305 }
306 
307 #define MAX_COREDUMP_LINE_LEN	40
308 
309 struct devcoredump_test_data {
310 	enum devcoredump_state state;
311 	unsigned int timeout;
312 	char data[MAX_COREDUMP_LINE_LEN];
313 };
314 
315 static inline void force_devcd_timeout(struct hci_dev *hdev,
316 				       unsigned int timeout)
317 {
318 #ifdef CONFIG_DEV_COREDUMP
319 	hdev->dump.timeout = secs_to_jiffies(timeout);
320 #endif
321 }
322 
323 static ssize_t force_devcd_write(struct file *file, const char __user *user_buf,
324 				 size_t count, loff_t *ppos)
325 {
326 	struct vhci_data *data = file->private_data;
327 	struct hci_dev *hdev = data->hdev;
328 	struct sk_buff *skb = NULL;
329 	struct devcoredump_test_data dump_data;
330 	size_t data_size;
331 	int ret;
332 
333 	if (count < offsetof(struct devcoredump_test_data, data) ||
334 	    count > sizeof(dump_data))
335 		return -EINVAL;
336 
337 	if (copy_from_user(&dump_data, user_buf, count))
338 		return -EFAULT;
339 
340 	switch (dump_data.state) {
341 	case HCI_DEVCOREDUMP_DONE:
342 	case HCI_DEVCOREDUMP_ABORT:
343 	case HCI_DEVCOREDUMP_TIMEOUT:
344 		break;
345 	default:
346 		return -EINVAL;
347 	}
348 
349 	data_size = count - offsetof(struct devcoredump_test_data, data);
350 
351 	skb = alloc_skb(data_size, GFP_ATOMIC);
352 	if (!skb)
353 		return -ENOMEM;
354 	skb_put_data(skb, &dump_data.data, data_size);
355 
356 	hci_devcd_register(hdev, vhci_coredump, vhci_coredump_hdr, NULL);
357 
358 	/* Force the devcoredump timeout */
359 	if (dump_data.timeout)
360 		force_devcd_timeout(hdev, dump_data.timeout);
361 
362 	ret = hci_devcd_init(hdev, skb->len);
363 	if (ret) {
364 		BT_ERR("Failed to generate devcoredump");
365 		kfree_skb(skb);
366 		return ret;
367 	}
368 
369 	hci_devcd_append(hdev, skb);
370 
371 	switch (dump_data.state) {
372 	case HCI_DEVCOREDUMP_DONE:
373 		hci_devcd_complete(hdev);
374 		break;
375 	case HCI_DEVCOREDUMP_ABORT:
376 		hci_devcd_abort(hdev);
377 		break;
378 	case HCI_DEVCOREDUMP_TIMEOUT:
379 		/* Do nothing */
380 		break;
381 	default:
382 		return -EINVAL;
383 	}
384 
385 	return count;
386 }
387 
388 static const struct file_operations force_devcoredump_fops = {
389 	.open		= simple_open,
390 	.write		= force_devcd_write,
391 };
392 
393 static void vhci_debugfs_init(struct vhci_data *data)
394 {
395 	struct hci_dev *hdev = data->hdev;
396 
397 	debugfs_create_file("force_suspend", 0644, hdev->debugfs, data,
398 			    &force_suspend_fops);
399 
400 	debugfs_create_file("force_wakeup", 0644, hdev->debugfs, data,
401 			    &force_wakeup_fops);
402 
403 	if (IS_ENABLED(CONFIG_BT_MSFTEXT))
404 		debugfs_create_file("msft_opcode", 0644, hdev->debugfs, data,
405 				    &msft_opcode_fops);
406 
407 	if (IS_ENABLED(CONFIG_BT_AOSPEXT))
408 		debugfs_create_file("aosp_capable", 0644, hdev->debugfs, data,
409 				    &aosp_capable_fops);
410 
411 	debugfs_create_file("force_devcoredump", 0644, hdev->debugfs, data,
412 			    &force_devcoredump_fops);
413 }
414 
415 static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
416 {
417 	struct hci_dev *hdev;
418 	struct sk_buff *skb;
419 
420 	if (data->hdev)
421 		return -EBADFD;
422 
423 	/* bits 2-5 are reserved (must be zero) */
424 	if (opcode & 0x3c)
425 		return -EINVAL;
426 
427 	skb = bt_skb_alloc(4, GFP_KERNEL);
428 	if (!skb)
429 		return -ENOMEM;
430 
431 	hdev = hci_alloc_dev();
432 	if (!hdev) {
433 		kfree_skb(skb);
434 		return -ENOMEM;
435 	}
436 
437 	data->hdev = hdev;
438 
439 	hdev->bus = HCI_VIRTUAL;
440 	hci_set_drvdata(hdev, data);
441 
442 	hdev->open  = vhci_open_dev;
443 	hdev->close = vhci_close_dev;
444 	hdev->flush = vhci_flush;
445 	hdev->send  = vhci_send_frame;
446 	hdev->get_data_path_id = vhci_get_data_path_id;
447 	hdev->get_codec_config_data = vhci_get_codec_config_data;
448 	hdev->wakeup = vhci_wakeup;
449 	hdev->setup = vhci_setup;
450 	hci_set_quirk(hdev, HCI_QUIRK_NON_PERSISTENT_SETUP);
451 	hci_set_quirk(hdev, HCI_QUIRK_SYNC_FLOWCTL_SUPPORTED);
452 
453 	/* bit 6 is for external configuration */
454 	if (opcode & 0x40)
455 		hci_set_quirk(hdev, HCI_QUIRK_EXTERNAL_CONFIG);
456 
457 	/* bit 7 is for raw device */
458 	if (opcode & 0x80)
459 		hci_set_quirk(hdev, HCI_QUIRK_RAW_DEVICE);
460 
461 	if (hci_register_dev(hdev) < 0) {
462 		BT_ERR("Can't register HCI device");
463 		hci_free_dev(hdev);
464 		data->hdev = NULL;
465 		kfree_skb(skb);
466 		return -EBUSY;
467 	}
468 
469 	if (!IS_ERR_OR_NULL(hdev->debugfs))
470 		vhci_debugfs_init(data);
471 
472 	hci_skb_pkt_type(skb) = HCI_VENDOR_PKT;
473 
474 	skb_put_u8(skb, 0xff);
475 	skb_put_u8(skb, opcode);
476 	put_unaligned_le16(hdev->id, skb_put(skb, 2));
477 	skb_queue_head(&data->readq, skb);
478 	atomic_inc(&data->initialized);
479 
480 	wake_up_interruptible(&data->read_wait);
481 	return 0;
482 }
483 
484 static int vhci_create_device(struct vhci_data *data, __u8 opcode)
485 {
486 	int err;
487 
488 	mutex_lock(&data->open_mutex);
489 	err = __vhci_create_device(data, opcode);
490 	mutex_unlock(&data->open_mutex);
491 
492 	return err;
493 }
494 
495 static inline ssize_t vhci_get_user(struct vhci_data *data,
496 				    struct iov_iter *from)
497 {
498 	size_t len = iov_iter_count(from);
499 	struct sk_buff *skb;
500 	__u8 pkt_type, opcode;
501 	int ret;
502 
503 	if (len < 2 || len > HCI_MAX_FRAME_SIZE)
504 		return -EINVAL;
505 
506 	skb = bt_skb_alloc(len, GFP_KERNEL);
507 	if (!skb)
508 		return -ENOMEM;
509 
510 	if (!copy_from_iter_full(skb_put(skb, len), len, from)) {
511 		kfree_skb(skb);
512 		return -EFAULT;
513 	}
514 
515 	pkt_type = *((__u8 *) skb->data);
516 	skb_pull(skb, 1);
517 
518 	switch (pkt_type) {
519 	case HCI_EVENT_PKT:
520 	case HCI_ACLDATA_PKT:
521 	case HCI_SCODATA_PKT:
522 	case HCI_ISODATA_PKT:
523 		if (!data->hdev) {
524 			kfree_skb(skb);
525 			return -ENODEV;
526 		}
527 
528 		hci_skb_pkt_type(skb) = pkt_type;
529 
530 		ret = hci_recv_frame(data->hdev, skb);
531 		break;
532 
533 	case HCI_VENDOR_PKT:
534 		cancel_delayed_work_sync(&data->open_timeout);
535 
536 		opcode = *((__u8 *) skb->data);
537 		skb_pull(skb, 1);
538 
539 		if (skb->len > 0) {
540 			kfree_skb(skb);
541 			return -EINVAL;
542 		}
543 
544 		kfree_skb(skb);
545 
546 		ret = vhci_create_device(data, opcode);
547 		break;
548 
549 	default:
550 		kfree_skb(skb);
551 		return -EINVAL;
552 	}
553 
554 	return (ret < 0) ? ret : len;
555 }
556 
557 static inline ssize_t vhci_put_user(struct vhci_data *data,
558 				    struct sk_buff *skb,
559 				    char __user *buf, int count)
560 {
561 	char __user *ptr = buf;
562 	int len;
563 
564 	len = min_t(unsigned int, skb->len, count);
565 
566 	if (copy_to_user(ptr, skb->data, len))
567 		return -EFAULT;
568 
569 	if (!data->hdev)
570 		return len;
571 
572 	data->hdev->stat.byte_tx += len;
573 
574 	switch (hci_skb_pkt_type(skb)) {
575 	case HCI_COMMAND_PKT:
576 		data->hdev->stat.cmd_tx++;
577 		break;
578 	case HCI_ACLDATA_PKT:
579 		data->hdev->stat.acl_tx++;
580 		break;
581 	case HCI_SCODATA_PKT:
582 		data->hdev->stat.sco_tx++;
583 		break;
584 	}
585 
586 	return len;
587 }
588 
589 static ssize_t vhci_read(struct file *file,
590 			 char __user *buf, size_t count, loff_t *pos)
591 {
592 	struct vhci_data *data = file->private_data;
593 	struct sk_buff *skb;
594 	ssize_t ret = 0;
595 
596 	while (count) {
597 		skb = skb_dequeue(&data->readq);
598 		if (skb) {
599 			ret = vhci_put_user(data, skb, buf, count);
600 			if (ret < 0)
601 				skb_queue_head(&data->readq, skb);
602 			else
603 				kfree_skb(skb);
604 			break;
605 		}
606 
607 		if (file->f_flags & O_NONBLOCK) {
608 			ret = -EAGAIN;
609 			break;
610 		}
611 
612 		ret = wait_event_interruptible(data->read_wait,
613 					       !skb_queue_empty(&data->readq));
614 		if (ret < 0)
615 			break;
616 	}
617 
618 	return ret;
619 }
620 
621 static ssize_t vhci_write(struct kiocb *iocb, struct iov_iter *from)
622 {
623 	struct file *file = iocb->ki_filp;
624 	struct vhci_data *data = file->private_data;
625 
626 	return vhci_get_user(data, from);
627 }
628 
629 static __poll_t vhci_poll(struct file *file, poll_table *wait)
630 {
631 	struct vhci_data *data = file->private_data;
632 
633 	poll_wait(file, &data->read_wait, wait);
634 
635 	if (!skb_queue_empty(&data->readq))
636 		return EPOLLIN | EPOLLRDNORM;
637 
638 	return EPOLLOUT | EPOLLWRNORM;
639 }
640 
641 static void vhci_open_timeout(struct work_struct *work)
642 {
643 	struct vhci_data *data = container_of(work, struct vhci_data,
644 					      open_timeout.work);
645 
646 	vhci_create_device(data, 0x00);
647 }
648 
649 static int vhci_open(struct inode *inode, struct file *file)
650 {
651 	struct vhci_data *data;
652 
653 	data = kzalloc_obj(*data);
654 	if (!data)
655 		return -ENOMEM;
656 
657 	skb_queue_head_init(&data->readq);
658 	init_waitqueue_head(&data->read_wait);
659 
660 	mutex_init(&data->open_mutex);
661 	INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout);
662 	INIT_WORK(&data->suspend_work, vhci_suspend_work);
663 
664 	file->private_data = data;
665 	nonseekable_open(inode, file);
666 
667 	schedule_delayed_work(&data->open_timeout, secs_to_jiffies(1));
668 
669 	return 0;
670 }
671 
672 static void vhci_debugfs_remove(struct hci_dev *hdev)
673 {
674 	debugfs_lookup_and_remove("force_suspend", hdev->debugfs);
675 
676 	debugfs_lookup_and_remove("force_wakeup", hdev->debugfs);
677 
678 	if (IS_ENABLED(CONFIG_BT_MSFTEXT))
679 		debugfs_lookup_and_remove("msft_opcode", hdev->debugfs);
680 
681 	if (IS_ENABLED(CONFIG_BT_AOSPEXT))
682 		debugfs_lookup_and_remove("aosp_capable", hdev->debugfs);
683 
684 	debugfs_lookup_and_remove("force_devcoredump", hdev->debugfs);
685 }
686 
687 static int vhci_release(struct inode *inode, struct file *file)
688 {
689 	struct vhci_data *data = file->private_data;
690 	struct hci_dev *hdev;
691 
692 	cancel_delayed_work_sync(&data->open_timeout);
693 	flush_work(&data->suspend_work);
694 
695 	hdev = data->hdev;
696 
697 	if (hdev) {
698 		if (!IS_ERR_OR_NULL(hdev->debugfs))
699 			vhci_debugfs_remove(hdev);
700 		hci_unregister_dev(hdev);
701 		hci_free_dev(hdev);
702 	}
703 
704 	skb_queue_purge(&data->readq);
705 	file->private_data = NULL;
706 	kfree(data);
707 
708 	return 0;
709 }
710 
711 static const struct file_operations vhci_fops = {
712 	.owner		= THIS_MODULE,
713 	.read		= vhci_read,
714 	.write_iter	= vhci_write,
715 	.poll		= vhci_poll,
716 	.open		= vhci_open,
717 	.release	= vhci_release,
718 };
719 
720 static struct miscdevice vhci_miscdev = {
721 	.name	= "vhci",
722 	.fops	= &vhci_fops,
723 	.minor	= VHCI_MINOR,
724 };
725 module_misc_device(vhci_miscdev);
726 
727 module_param(amp, bool, 0644);
728 MODULE_PARM_DESC(amp, "Create AMP controller device");
729 
730 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
731 MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION);
732 MODULE_VERSION(VERSION);
733 MODULE_LICENSE("GPL");
734 MODULE_ALIAS("devname:vhci");
735 MODULE_ALIAS_MISCDEV(VHCI_MINOR);
736